Reika is an Element and pilot of Aquarion. Her non-canon past life is Scorpius.
Reika has navy colored hair and gray eyes. She wears a white, long sleeved, collared blouse with a purple necktie, purple skirt, purple pants, and silver colored shoes. When she is in a vector, she wears a purple bodysuit with gray wrist guards.
Reika is a sensitive young woman who believes she carries a strange ability of causing misfortune to those around her. She forces herself to avoid people approaching her, with the exception of Sirius, who nurtures strong feelings for her and spends many occasions attempting to connect with her. She eventually manages to overcome her sense of rotten luck and turn it into a weapon when piloting the Aquarion Mars.
She appears to be able to see the weakness of Harvest Beasts, how many people a the Harvest Beast hold, as well as mind telekinesis.
Reika appears to have romantic feelings for Sirius and tries to get close to him. However, Silvia attempts to sabotage any attempts for them to get closer because she believes Reika is "bad luck".
She and Glen appeared to be close friends before the events in episode 1, Memories of Heavenly Wings. She blames his accident in episode on her bad luck. Glen gave her a charm to ward against bad luck, and she treasures it dearly.
Apollo and Reika appear to be friends, Apollo not caring that she "causes misfortune". In the OVA, it is Reika who stabs Apollo in his sleep (however she was under Toma's control at the time and didn't remember doing it.) She believed that she was the reincarnation of Celiane until Toma told her that she was instead the reincarnation of Scorpius, the one who killed Appollonius because he desired the power of the Shadow Angels to benefit his people.
Reika and Pierre appear to be friends throughout the anime. In the OVA, it's Pierre who rips off the feather that was implanted into her.
Reika is Tsugumi's mentor and friend. Reika tries her best in teaching Tsugumi how to pilot Aquarion, and in turn, Tsugumi deeply admires Reika.
- In the original Japanese version, her actual name is Hong Lihua. There has been no designated reason as to why her name was changed to Kou Reika.
- Her name means "Lovely Red Flower"
- This applies to both the Pinyin and Japanese spelling/pronunciation of her name.